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Original Research ARTICLE

Front. Neural Circuits, 19 April 2012 | http://dx.doi.org/10.3389/fncir.2012.00018

Optophysiological analysis of associational circuits in the olfactory cortex

Akari Hagiwara*, Sumon K. Pal, Tomokazu F. Sato, Martin Wienisch and Venkatesh N. Murthy*
  • Department of Molecular and Cellular Biology, Center for Brain Science, Harvard University, Cambridge, MA, USA

Primary olfactory cortical areas receive direct input from the olfactory bulb, but also have extensive associational connections that have been mainly studied with classical anatomical methods. Here, we shed light on the functional properties of associational connections in the anterior and posterior piriform cortices (aPC and pPC) using optophysiological methods. We found that the aPC receives dense functional connections from the anterior olfactory nucleus (AON), a major hub in olfactory cortical circuits. The local recurrent connectivity within the aPC, long invoked in cortical autoassociative models, is sparse and weak. By contrast, the pPC receives negligible input from the AON, but has dense connections from the aPC as well as more local recurrent connections than the aPC. Finally, there are negligible functional connections from the pPC to aPC. Our study provides a circuit basis for a more sensory role for the aPC in odor processing and an associative role for the pPC.

Keywords: piriform cortex, anterior olfactory nucleus, recurrent connection, channelrhodopsin-2, calcium imaging, odor processing

Citation: Hagiwara A, Pal SK, Sato TF, Wienisch M and Murthy VN (2012) Optophysiological analysis of associational circuits in the olfactory cortex. Front. Neural Circuits 6:18. doi: 10.3389/fncir.2012.00018

Received: 19 January 2012; Accepted: 26 March 2012;
Published online: 19 April 2012.

Edited by:

Gordon M. Shepherd, Yale University School of Medicine, USA

Reviewed by:

Donald A. Wilson, New York University School of Medicine, USA
Peter Brunjes, University of Virginia, USA

Copyright: © 2012 Hagiwara, Pal, Sato, Wienisch and Murthy. This is an open-access article distributed under the terms of the Creative Commons Attribution Non Commercial License, which permits non-commercial use, distribution, and reproduction in other forums, provided the original authors and source are credited.

*Correspondence: Venkatesh N. Murthy, Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA. e-mail: vnmurthy@fas.harvard.edu
Akari Hagiwara, Faculty of Medicine, Department of Biochemistry, University of Yamanashi, 1110 Shimokato, Chuo, Yamanashi, 409-3898, Japan. e-mail: akarih@yamanashi.ac.jp

These authors contributed equally to this work